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Installing Seats

by Roger Moment

Originally published in the Austin-Healey Magazine, January 1994

There are three aspects to restoration:

  • Knowledge of how things were originally assembled, what parts were used, what was the sequence of assembly, and what materials/colors were used.

  • Finding the correct items or reproducing them, if they are no longer available.

  • Quality of workmanship on refinishing and installation.

In many ways, the most difficult task is finding information on how cars were originally put together.

Most cars that lose points in Concours do so because people didn't know what was correct and did not take the time or know how to ferret out the information. While the Concours Standards try to answer questions regarding originality, they can never address all the thousands of details that go into a car.

The topic for today is installation of seats (not a very interesting subject, unless you have a BN1 or BN2). This is because the passenger seats of these models did not sit on adjustable tracks and the various collections of wooden blocks (many of which are often missing) can easily lead to having the seat too low or incorrectly assembled to the floor.

Figure 1 shows how the adjustable seat tracks are installed. These apply to the driver's side of the series BN 1 / 2, and both sides of all six cylinder cars. The large rectangular plate sets on top of the tar paper floor covering and in turn, has a 1-1/8" by 14-1/2" by 5/ 16" thick wooden packing piece fitted between it and the seat track. The track is secured to the floor by special block-like nuts, whose cylindrical section slips up through the floor holes and the large packing strip holes.

The passenger side of BN 1 / 2 cars has no adjustable track. Instead, two wooden packing blocks are used, one identical to that on the driver's side and the other very similar, but 5/8" thick, as shown in Figure 2. This latter piece also has two Tee nuts pressed into the bottom side. The complete parts list below (for cars with body number 100 1 and higher) shows plain and "13"washers, as well as two sizes of blots - 1" and 1-1/4".

Installation of the passenger seat then proceeds as follows. The thick wooden packing strip sets on top of the metal plate and is bolted to the floor over the tar paper. The 1-1/4" bolts are used, with the "D" washers on the inside set, as the holes pass through very close to the main frame box. The three plain washers, PWZ204, are used under the floor for the outer set. Next the two5/16" thick packing strips are placed so that their large holes fit over the three bolts heads and washers holding the thicker strips to the floor. The seat bottom is then bolted to the Tee nuts of the thick packing pieces, using the 1" bolts and a plain washer. However, note that there are only 4 such bolts holding the seat bottom, not six as is the case where seats are bolted to adjustable tracks.

One final detail remains. The bolts, in all cases have 1/4-28 threads and hexagonal heads. I was not able to find Tee nuts with this thread but did locate some with 1/4-20 threads. The problem with this is that the heads of the four bolts holding the seat base will show, when the seat cushion is removed and are supposed to have a depressed circular dimple common to all British bolts used on Healeys. These bolts only come with 1/4-28 threads. The solution is to buy some 1/4-20 Tee nuts and fill their thread with a thin coating of braze metal (a MAPP gas torch is fine for doing this). Then the holes can be re-drilled with a #3 drill (0.213") and tapped to 1/4-28. This little extra step allows the proper British bolts to be used and preserves the correct appearance without sacrificing strength of the nut.

While this entire issue will hold little interest for most people, it does illustrate one detail that can distinguish the more perfect restoration from other nice ones. And it also explains the reason behind the large holes that one finds in the thin packing strips. Just one more little bit of the Healey puzzle sorted out.

Not what you were looking for? Don't forget you can check our back issues using the AHCUSA Magazine Index.

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